Thermostat and similar control device



P. DODGE.

THERMOSTAT AND SIMELAR CONTROL DEViCE.

APPLICATION FILED MAY 13, 1920.

1,397,407, Patented Nov. 15,1921.

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8 wuenboz P. DODGE.

THERMOSTAT AND SIMILAR CONTROL DEVICE.

APPLICATION FILED MAY 13. 1920.

1,397,407, Patented Nov. 15, 1921.

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UNITED STATQS PATENT GFEIQE.

PARKER'DODGE, OF WASHINGTON, DISTRICT OF COLUIVIBIA, ASSIGNOR TO THE JOHNSON SERVICE 00., OF MILXVAUKEE, WISCONSIN, A CORPORATION OF W ISCONSLN. I

TEERMOSTAT AND SIMILAR CONTROL DEVICE.

Specification of Letters Patent.

Patented Nov. 15, 1921.

Application filed May 1 3, 1920. Serial No. 381,200.

To aZZ whom a m mwe'm f Be it known that I, PARKER Doncn, a citizen of the United States, residing at Washington, in the District of Columbia, have invented certain. new and useful Improvements in 'Ihermostats'and Similar Control Devices, of which the following is a specification. i I:

This invention relates tothermostats and similar control devices; and particularly to means for shifting the mechanism either manually or by a clock to bring it into active relation with either of two individually adjustable stops for determining the temperature maintained by the thermostat.

The invention is particularly applicable to so called night and day thermostats for domestic use, and offers in addition to simple inexpensive construction, certain 1 practical operative advantages. The user can set the device manually to either night or day setting at any time 'without deranging the relation of the clock to the device. For example the device may be set for night temperature before the time for actuation by the clock, and the clock will automatically restore the day setting at the usual time in the morning. Either the night or the day adjustment may be changed at any time without any manipulation other than the turning of the corresponding graduated head. The user can never apply force to any of the delicate parts of the device, either in making adjustments or in shifting from night to day setting. The shifting mechanism indicates directly whether the device is set for night or for day.

The device may be designed to receive with only one minor change, either of two types of clock, one requiring to be wound daily and intended merely to shift the device fromnight to day setting in the early morning, and the other of the eight day variety designed to shift the thermostat back and forth night and morning. This detail permits the manufacture of two types of in struments, one relatively cheap and the other more expensive, both of which have many of their parts other than the clock in common. This feature leads to economy in manufacture and permits the instruments to be changed from one type to another by the substitution of a different clock and shift rod. v

In the accompanying drawings I illustrate an electric thermostat embodying the invention in the form including an eight-day clock.

In the drawings:

Figure 1' is a front elevation of the complete device;

Fig. 2 is a section on the line 2-2 of Fi 3;

' big. 3 is a section on the line 33 of Fig. ,2;

Fig. 4 is a fragmentary front elevation of the device with the clock removed;

Fig. 5 is a plan view of the shift rod.

Fig. 6 is a front elevation of the shift rod.

Fig. 7 is a front elevation of the carrier arm.

Fig. 8 is a side elevation of the carrier arm, and

Fig. 9 is a view of the shift spring.

The wall frame includes a back plate 11 and a front plate 12 connected by the side members 13. The side members 13 have slots let for the circulation of air. The front plate has an annular rim 15 to position the clock 16, the rim 15 being formed with holes 17 to receive the spring detents 18, which hold the clock in place. The openings 19 and 20 are for convenience in assembling the device, the opening 19 giving access to the screw which holds the carrier arm and the opening 20 giving clearance for the shift spring retaining tube. The opening 21 is to receive the arbor of the clock which actuates the shift rod.

At the upper end of back plate 11 are two stop posts 22 which may be cast integrally with the base. Threaded in the left hand post is the high temperature or day stop screw 23 which has a graduated knob 2%.

Threaded in the right hand post is the low- The post 27 carries pivoted on it in any usual manner, for example by a shouldered screw '28 the thermostat carrier arm 29. These parts are so adjusted by means of a spring washer 30 that a slight frictional resistance is offered to the movement: of the arm sufiicient to keep the arm from wavering at the moment of shifting. The upper portion of arm 29 terminates in a head 31 which swings between the ends of stop screws 23 and 25. The lower end of arm 29 is forked and terminates in two rounded heads 32 which straddle a fiat portion 33 of the shift-rod indicated generally by'the numeral 34. The heads 32 work between two stops '35f'an-d '36 on rod 34, which are so spaced apart as to allow the rod some lost motion with reference to the arm. The interengagement of the forked end of the arm withthe fiatson the 'rod holdsthe rod against rotation.

The rod 34 has, to the left of stop 35, -a

' yoke 37 with two offset teeth 38 and 39. At

the extreme left end it terminatesin .a cylindrical portion 40 guided on the side 13 of the frame. The, rod 34 has to the rightof stop 36 a reverse'ly tapered enlargement 41, shown as two truncated cones placed base to base. This enlargement coacts with an annular coil spring 42 confined in a channel "43 in a"t1'1be"44 which surrounds the enlargement.

The tube;44 is flanged-at 45 and is held by a plug-46 screwed into wall 13 of the frame. The plug 46 also vhaska central opening to guide the right end portion 47 of the rod 34 andaffords -a simple means of assembling the parts.

The spring .42.-and reversely tapered enlargement 41 form a convenient reversible spring :mechanism, a term which I use in the claims to define a ,mechanism, capable of exerting resilient pressure in reverse directions, accordingas it is shifted to one orthe other of twodiiferent positions. The specific device "illustrated and many variations of it, involving changesin the forms of the reversely tapered enlargement, and of the contracting spring member, have been used for a wide range of purposes. I have illustrated the simplest .one known to me as typical of the class and contemplate substitutions of known equivalents.

The parts are so proportioned that when the projecting end of the rod 34 is forced in, the spring 42 will first ride over the middle o'f-enlargement 41. Stop 35 or 36 (as the case may be) will then pick up arm 29 and shift it until head 31 is arrested by the opposed stop. At this point the end of rod 34 will be completely housed so that pressure can no longer be applied to it. The wall frame thus serves as a guard to prevent the exertion of undue force upon the shift rod 34. or through the shift rod upon other parts of the device. The provision of lost motion made blackand white, respectively, to give 'ar-visual indication at a distance. '34 thus serves as convenient manually op- The rod erable means for shifting the thermostat by reversing the reversible spring mechanism.

The thermostat chosen for illustration is a bimetallic-bar 48, of familiar type carried on a stud 49--on arm 29. The thermostatic bar 48 has at its free end a contact 50 which swings between two adjustable contact screws 51 and 52 threaded in posts 53 and 54. The posts 53 and-54 are insulated from the back plate 11 at 55, and respectively, constitute terminal connections for two circuits; The screw 58 on backpla'te 11 serves as a ,connection common to both these circuits. The function of thermostat arm 48 is to close these ci-rcuitsin alternation. This function, the modes of connecting the circuits and the details of theaccessory and controlled apparatus are familiar to those skilled in this art and hence are not illustrated.

*The clock 16 includes an eight day movement and ,a secondary spring motor train controlled thereby. The arbor 56 which projects from the back of the clock is driven by this secondary train and the clock releases this train twice in each 24 hours in such manner that arbor 56 turns through 180 and then comes to rest. 'It is desirable that the clock be capable of releasing the secondary train at different hours in alternate twelve-hour periods, and that both times of release be capable of adjustment. Such clocks are known in the art and include various-meansfor determining and adjusting the time of release of the secondary train. Since the details of the clock are not a part of the present invention they are not described in detail.

The arbor 56 carries an arm 57 shown in Fig. 2 in its normal position of rest. In this figure the thermostat is shown in its night setting. At the hour in the morning determined by the adjustment of the clock (say 6 a. m.) arbor 56 is released and turns one half turn. Arm 57'strikes tooth 39 and shifts rod 34 to the right far enough to cause spring 42 to roll over the middle of enlargement'41. The spring 42 completes the shifting movement. In the following evening at the-hour determined by the adjustment of the clock (say 10 p. m) thearbor 56 is released for another half turn. Arm 57 strikes tooth 38 and shifts rod 34 to the left,spring 42 completing the movement as before. The device thus operates automatically night and morning so long as the clock runs.

Since the arm 57 when at rest stands in a horizontal position the rod 34 may be shifted manually to change the setting from day to night or the reverse without overcoming any resistance except that of the reversible spring mechanism. It will be observed that if such a reversal be made be fore the time of automatic actuation by the clock the clock will function at the time setbut will not shift the rod 34. Thus the clock automatically resumes the correct phase relation with the shifting mechanism.

This is .an' important advantage, because regardless of any manual shifting the clock can never operate to establish the night adjustment during the day, or the day adjustment during the night. The possibility of making, forexample, the night adjustment at a time earlier than that automatically affected by the clock is a useful feature of the invention.

To provide a cheaper instrument using the same main parts I substitute for the rod 34 a rod lacking the tooth 38 but otherwise identical, and for the eight day clock I substitute a common alarm clock in which 56 is the alarm winding arbor. Arm 57 serves as the alarm winding key. At night the clock is wound and set, the rod 34 is manually shifted to the left and the clock put in position. In the morning the release of the alarm train causes the Winding arbor to turn, and this shifts rod 3 1 to the right, where it remains regardless of continued rotation of arbor 56. Because of the relative cheapness of alarm clocks such an embodiment of the invention is quite inexpensive.

The main inventive ideas are in the adjust ing and shifting mechanisms and their relation to clock mechanisms to secure automatic shifting. Obviously these principles can be used with other adjustable automatic control devices, such for example, as hygrostats, and with devices functioning by the control of pneumatic as well as electric motive energy. Such substitutions are contemplated by me.

Thermostats and like devices are capable of adjustment in various different ways. For example, in electric thermostats, the moving element may be shifted with reference to fixed contacts, or the contacts may be movable and the thermostat have a fixed support. or both thermostat and contacts may be capable of simultaneous adjustment. This is familiar to those skilled in the art. In all these cases the adjustment is dependent on the motion of some movable member. In the present case the arm 29 is such movable member. and I use the term movable member in the claims in its generic VhlLABLE so? sense to define this part or its functional equivalent.

Having thus described my invention What I claim is:

1. The combination of an automatic control device including a responsive element a movable member for adjusting the action of said element; stops serving to limit the movement of said member in opposite directions; a reversible spring mechanism serving to hold said member against each of said stops in alternation, as the action of the spring mechanism is reversed; and means for shifting said spring mechanism to reverse its action.

2. The combination of an automatic control device including a responsive element; a movable member for adjusting the action of said element stops serving to limit the movement of said member in opposite directions; a reversible spring mechanism serving to hold said member against each of said stops in alternation, as the action of the spring mechanism is reversed; and manually operable means for shifting said spring mechanism alternately in reverse directions to reverse its action.

3. The combination of an automatic control device including a responsive element; a movable member for adjusting the action of said element; stops serving to limit the movement of said member in opposite directions; a reversible spring mechanism serving to hold said member against each of said stops in alternation, as the action of the sprin mechanism is reversed; and time controlled means serving to shift said spring mechanism to reverse its action.

4. The combination of an automatic control device including a responsive element; a movable member for adjusting the action of said element; stops serving to limit the movement of said member in opposite directions; a reversible spring mechanism serving to hold said member against each of said stops in alternation, as the action of the spring mechanism is reversed; and time controlled means serving to shift said spring mechanism periodically back and forth to reverse its action repeatedly.

5. The combination of an automatic control device including a responsive element; a movable member for adjusting the action of said element; stops serving to limit the movement of said member in opposite directions; a reversible spring mechanism serving to hold said member against each of said stops in alternation, as the action of the spring mechanism is reversed; manually operable means for shifting said spring mechanism to reverse its action; and a movable clock-controlled member serving when actuated by the clock to engage and shift said manually operable means.

6. The combination of an automatic control device including alresponsive element a movable member for adjusting the action of said element; stops serving 7 to limit the movement of said member in opposite directions; a-reversible spring mechanism; a lost motion connection between-said spring mechanism and'said movable member; and means for shifting said spring mechanism to reverse its action.

;7.'Tl-he combination'of anautomatic control device including a responsive element; a movable-member for-adjusting the action of'said element; stops serving to limit the movement-of-said member in opposite directions; a reversible spring mechanism; a lost motion c'onnection betWeen-said spring mechanism and saidmovable member manually operable means for shifting said spring mechanism; and a guard serving to limit the manual actuation bf said sprin mechanism to aportion of its'ranjgeEbut-su cient to insure reversal -oithe action 0f the spring mechanism. i

""8; The combination of an 1 automatic control device includinga responsive element a movable member for-adjusting the action of said element; stops serving to limit the-movement=-of=said :member in opposite directions; a reversible spring mechanism; a 10st motion connection between said spring mechanism and said :movable member; manually -operable means for shifting said spring -mecha ni'sm {to reverse the isame a guar serving to limit themanual-operation of said spring mechanism to a portion of itsrange of action s er cos less than the Whole, but sufiicient-to insure reversal; and a movable clock controlled member normally at rest disengaged from said manually operable means and serving whenactuated by the clock to engage and shift the same.

"9. The combination of an automatic control device including a responsive element; a movable member for adjusting-the action of said-element; individually adjustable stops serving to limit the movement of said memher in opposite directions; a reversible spring mechanism; a lost motion connection between said spring mechanism and said movable member; and means for shifting said spring mechanism to reverse its action.

10; The combination of an automatic control device including a responsive element; a movable-member for adjusting the action of said element; individually adjustable stops serving'to limit the movement of said member in opposite directions; a reversible springmechanism; a lost motion connection between said spring mechanism and said movable -member manually operable means for shiftingsaid spring mechanism; and-a guard serving to limit the manual-actuation of-saidspring mechanism to a portion of-its total range of motion sufficient to secure reversal of the spring mechanism but less than said total range as defined by the closest setting of said adjustable stops.

In testimony whereof I have signed my name-to this specification.

PARKER DODGE. 

